Polymerized styrene-polyisoprene resin product



April 27, 1943. F. J. SODAY 2,317,857

ropmmnlz sn STYRENE-POLYISOPRENE REsm fndnucws Filed Dec. 17, 1938ISOPRVENE' (CATALYST) STYRENE CATALYTICALLY PARTIALLY POLYMERIZEDISOPRENE (HEAT AND/QR CATALYST) POLYMERIZED STYRENE POLY] SOPRENE RESINPRODUCT INVENTOIR'I FRANK J. SODAY ATTORNEY.

Patented Apr. 27, 1943 POLYMERI ZED STYRENE POLYISO PRENE RESIN PRODUCTFrank J. Soday, Upper Darby, Pa., assignor to The United Gas ImprovementCompany, a corporation of Pennsylvania Application December 17, 1938,Serial No. 246,501 20 Claims. (Cl. 260-86) This invention relates to anew composition of matter and a method for its preparation.

More particularly, this invention pertains to resins resulting fromreacting monomeric styrene with isoprene which has been partiallypolymerized catalytically. Such material will be referred to herein aspartially polymerized isoprene.

It is an object of this invention to provide a new type of syntheticresin. It is afurther object of this invention to provide resins havingutility in industrial fields, and particularly in the molding and liquidcoating composition fields.

Moreparticularly, it is an object of this invention to provide varnishand lacquer resins possessing excellent alkali, acid, and waterresistant properties. It is also a particular object of this inventionto provide molding resins which may be used with or without plasticizingagents or lubricants. It is a further object of this invention toprovide resins adapted to produce a smooth surface pleasing inappearance. A further object of the invention is to provide a moldingresin with substantially non-shrinking properties.

Still another object of this invention is to provide resins the color ofwhich may be readily controlled and varied.

A still further object ofthe invention is to provide resins compatiblewith a wide variety of additive agents such as fillers, decorativeconstituents, pigments, softening agents, plasticizers, and the like.

Another object of the invention is to provide a process for preparingresins of the above char acter.

Still other objects will become apparent to those skilled in the artfrom the following description and illustrative examples.

This invention is based upon the discovery that 7 new synthetic resinshaving highly desirable properties may be prepared upon reactingmonomeric styrene with isoprene which has been previously partiallypolymerized catalytically.

By partially polymerized isoprene is meant isoprene which hasbeensubjected to catalytic polymerization conditions sufiicient to changeits chemical constitution from monomeric isoprene, said polymerizationconditions, however,.being' insufficient to render the polymerizedmaterial incapable of further reaction.

The properties of the resulting resins vary somewhat with change inpolymerization conditions, both with respect to the initial partialpolymerization of isoprene and the subsequent poly+ merization ofmonomeric styrene and the partially polymerized isoprene.

' insoluble polymers or gels 7 quality.

For? example, the final resins will have increasingly higher meltingpoints with increasingly .greater initial polymerization of isoprene.

Furthermore, the relative proportions of monomeric styrene and partiallypolymerized isoprene reflect themselves in the properties of theresultant resinous compounds to a large extent. For example, the resinresulting from reacting parts of monomeric styrene with 40 parts ofpartially polymerized isoprene results in a resinous compound which isparticularly suitable for molding or casting. On the other hand, a resinresulting from reacting 40 parts of monomeric styrene with 60 parts ofpartially polymerized isoprene is particularly suitable for varnish andlacquer purposes. In other words, larger proportions of monomericstyrene result in resins more particularly suited for molding andcasting purposes whereas larger proportions of partially polymerizedisoprene result in the production of resins more particularly suited forvarnish and lacquer purposes.

Other factors which will have a modifying influence are the manner inwhich the initial and final polymerizations are conducted, theconcentration and relative purity of the materials undergoingpolymerization, the nature and quantity of catalyst employed,temperature range, reaction time, and the like.

For example, drastic conditions with respect to temperature,concentration of reactants, proportion of catalyst, and reaction time,may result in instead of the more desirable soluble resins.

Isoprene employed in the preparation of my new resins may be obtainedfrom any suitable source. For instance, it may be obtained from thepyrogenic decomposition of rubber, or from fractions obtained upon thefractionation of 'condensates obtained in the manufacture of carburettedwater gas, oil gas, refinery gas, or coke oven gas, or from similarsources. Such fractions will be referred to herein generally as lightoil isoprene fractions. Fractions obtained in the manufacture of oil gasare particularly preferred.

Hydrocarbon fractions containing from 5 to of isoprene may besuccessfully used in the production of the herein described partiallypolymerized isoprene, although, in of fractions containing from 50 to100% isoprene is preferred for the production of resins of highFractions in which isoprene is the only diolefine present are preferred,although fractions containing a lesser quantity of butadiene,cyclogeneral, the use.

pentadiene or piperylene, or any combination of two or more of these, orsimilar materials may be employe'd without departing from the spirit ofthe invention.

The presence of olefines, such as oleiines having five carbon atoms,does not detrimentally influence the reaction, but such oieflnes mayactually take part in the reaction and become a part of the resinousproduct.

The accompanying drawing represents a flow sheet of my invention in itsbroader aspects. As clearly shown, an initial step comprisescatalytically partially polymerizing isoprene. The resulting product andstyrene are thereafter subiected to further polymerization employingheat and/or a catalyst to obtain a product which is my novel polymerizedstyrene-polyisoprene resin having very desirable characteristics for usein various arts.

INITIAL POLYMERIZATION OE ISOPRENE should not exceed 70 C.; theconcentration of isoprene should rarely exceed 80% by weight of thetotal solution, and the concentration of catalyst, which is preferablyuniformly distributed, should rarely exceed by weight of the isoprenepresent, although these values are not to be considered as fixed limits.

Two or more of the foregoing catalysts might be employed.

The catalytic partial polymerization may be carried out in the liquidstateor in the vapor state, or both, and in the presence or absence ofsolvents. The catalytic partial polymerization also may be carried outin the emulsion state.

The partial polymerization ofisoprene in a light oil isoprene fractionis illustrated in the following example.

I Example 1 -A light oil isoprene fraction obtained in the manufactureof oil gas and containing 63.5% byweight of isoprene, 28.4% by weight ofoleflnes, and 8.1% by weight of parafiin hydrocarbons was employed.Fifty parts by weight of this isoprene fraction was polymerized byadding it to a mixture containing approximately one part by weight ofboron trifluoride-diethyl ether complex and 60 parts by weight oftoluene while maintaining the temperature of this mixture within a rangeof l to 7 C., and agitating during a 6-minute period of addition.Agitation was continued at this temperature for a period ofapproximately 21 hours after which the catalyst was hydrolyzed by theaddition of water. This was followed by approximately 30 minutes ofcontinuous agitation after which the resultant mixture containingpartially polymerized isoprene and unpolymerized constituents was driedby the addition of a small quantity of lime, with agitation,,for aperiod of approximately 1 hour.

All solid extraneous matter was thereafter removed by flltration.

The fraction containing partially polymerized isoprene, in addition tounpolymerized material,

was employed in the preparation of a styrenepolyisoprene resin as willbe more fully set forth hereinafter in Example 2.

On the other hand, the unpolymerized material may be wholly or partlyremoved prior to the final polymerization step.

The styrene employed in 'theproduction of my new resins may be obtainedfrom any suitable source, and may be in the form of pure or commerciallyor technically pure styrene, or in the form of a solution or a fractionsuch as obtained from light oil or a mixture of light oil hydrocarbons.The source of light oil may be the same as in the case of isoprene.

- Styrene fractions obtained by the distillation of light oil and havingboiling ranges between I 125 to 165 C. have been satisfactorily employedin the preparation of my styrene-polylsoprene resins. Resins havingespecially desirable properties have been obtained when employingstyrene fractions having boiling ranges between to 150 C. Even moredesirable properties are secured in the final resins when the styrenefractions have boiling ranges between 142 to 145 C.

Accordingly, the use of substantially pure styrene is preferred whencommercially feasible, particularly for resins of the molding type.

POLYMERIZATION or STYRENE AND PARTIALLY POLYMERIZED IsoPimNnPolymerization of monomeric styrene and partially polymerized isopreneis preferably carried out by application of heat, although the reactionmay be carried out through the use of catalysts with or without theapplication of heat, without departing from the broad concept of theinvention.

The polymerization may be carried out in the liquid state or in thevapor state, or both, and in the presence or absence of solvents. Thepoly merization also may be carried out in the emulsion state.

When the polymerization of styrene and partially polymerized isoprene iseffected by the application of heat, a temperature between 50 to 250 C.is preferred. Temperatures between '75; and 200 C. are found to beparticularly suitab e.

The reaction time may be varied over very wide limits, depending uponthe extent of the polymerization desired.

The following examples tion of my new resins.

Example 2 Approximately 30 parts by weight of a styrene fractionobtained from light oil and containing approximately 65% styrene, wasmixed with approximately 13' parts by weight of a partially illustratethe formapolyinerized isoprene fraction similar to that prepared by theprocedure given in Example 1. This mixture was placed in a glass bomband sealed in an atmosphere of nitrogen. The bomb was heated for aperiodof ten days at a temperature of approximately 100 C. Unpolymer--ized material was removed from the resulting mass by vaporization at atemperature of approximately 100 C. and a pressure of approxi or 2,000pounds per square inch. The resulting object was mottled in appearancehaving white and lemon-yellow colors, very beautiful in appearance. Thisresin was tough and hard and took a very high polish.

, Example 3 A styrene-polyisoprene resin having properties making itvery suitable for use in varnishes and lacquers was prepared as follows.

Approximately 9 parts by weight of a. styrene fraction obtained fromlight oil and containing approximately 65% styrene by weight was mixedwith approximately 35 parts by weight of a par-' sure of 1.0 mm. ofmercury, absolute. There was obtained a solid resin'in quantityequivalent to approximately 11 parts by weight. This resin possessedexcellent properties for use as a protective. coating for wood, metaland similar surfaces due to its high alkali, acid and water resistingproperties.

Example 4 'An extremely tough molding resin of relatively high meltingpoint was prepared as follows.

A partially polymerized isoprene fraction prepared as described inExample 1 was steam distilled to remove unpolymerized material. Tenparts by weight of this concentrated partially polymerized isoprene wasmixed with approximately 90 parts by weight of substantially 100%styrene, which had been obtained by concentration of a styrene fractionsecured from light oil. This mixture was placed in' a glass bomb andsealed in an atmosphere of nitrogen, and heated for eight days at atemperature oi' approximately 100 C. followed by-heating for two days ata temperature of'approximately 145 C. The reactants were thus completelypolymerized. The resulting resin was opaque, and resembled ivory inappearance. y

This resin was found to be of very high quality for molding purposes,and was characteristic of a styrene-polyisoprene resin in which the'predominant constituent is styrene.

Example 5 in Examples 2 and 3. There was thus obtained approximately 130parts by weight of a solid resin which, when molded at a temperature ofapproximately 185 C. and a pressure of 2,000 pounds per square inch,yielded an object resembling ivory in appearance. This object had anexceptionally smooth, hard, and tough surface and took a very highpolish.

isoprene.

Green produced through the addition to Holding resins made in accordancewith my invention are characterized not only by hardness. toughness,appearance, ability to take .a high polish, good molding properties, andinert characteristics, but also in imparting a warm and pleasingsensation to the touch. The latter is extremely important in the trade.

My new resins may be prepared in many desirable color combinations.Color may be obtained either naturally or artificially. Natural colorsmay be secured by varying the source and qualityof either the styrene orthe isoprene, or

both. Either plain or mottled color combinations may be obtained asshown in the foregoing examples.

- For example, the polymerization of a mixture containing parts ofmonomeric styrene, in the form of a 65% light oil styrene fraction, and20 parts of partially polymerized isoprene, in the form of a 20%solution in toluene, gave an opaque resin with a mottled yellowappearance. The mottled eilect was apparently produced by the dispersionof a colorless phase in a second phase which was colored.

Resins, which are milk-white in color and which resemble ivory-inappearance, may be pre-' pared by polymerizing mixtures containing puremonomeric styrene and partially polymerized Artificial colors and colorcombinations may be my new resins of suitable chemical compounds.

Coloring materials, such'as-organic dyes, inorganic dyes, pigments, andlakes, may be added to any one or more of the reactants, or to thereaction mixture at any stage, but preferably prior to completepolymerization.

As a rule organic dyes and other organic coloring bodies produce resinswith pastel shades.

The coloring compound may, of course, be

added to the unpolymerized isoprene, and may or may not be supplementedduring the secondary polymerization reaction, as desired.

If desired, the coloring material itself may be prepared in situ byadding the necessary materials to the polymerization reaction.

As an example, a short list of suitable coloring materials is given inthe following table.

TABLE I Mono am.

Mono azo.

'lriphenylmethane.

yron Diphenyl amine.

Orange Yellow....

Mottled clients may be obtained by adding coloring material to thepolymerization mass at a stage in the polymerization reaction afterwhich obtain the desired result. In this connection, in-,

hibitors may be employed to retard an otherwise too hasty reaction.

A proper choice of polymerizing conditions will enable almost any typeof coloring material to be used.

In addition to coloring materials, other additives may be incorporated,such as fillers, of which asbestos, mica, wood flour, cotton linters,and fabric waste are examples.

A decorative filler functioning very-much on the order of a coloringmaterial may be added, with or without othercoloring matter. Examples ofdecorative fillers are pearl essence and chitin extracts.

- Furthermore, other agents such as mold lubricants, softeners,plasticizers, and the like, may also be added at any stage of thepolymerization process.

While the use of heat as a polymerizing agent is preferred when reactingstyrene with catalytically partially polymerized isoprene, otherpolymerizing agents may be employed if desired either with or withoutthe application of heat.

For instance, polymerization catalysts, such as metallic halides,metallic halide-organic solvent complexes, organic peroxides, contactmaterials, ultra violet light, ultra sonics, mineral acids, mineralacid-organic solvent mixtures, active metals, etc., may be employed.

Examples of catalysts which may be employed in either the initial orfinal polymerization reaction are acid-acting metallic halides such asfor example aluminum chloride, aluminum bromide, stannic chloride, borontrifluoride, boron trichloride, zinc chloride, ferric chloride, andorganic solvent complexes of the foregoing metallic halides. Examples ofother catalysts which may be employed in the final polymerization arepinene peroxide, benzoyl peroxide, clay, activated clay, activatedcarbon, activated alumina, silica gel, fullers earth, diatomaceousearth, sulfuric acid, phosphoric acid, sulfuric acid-diethyl ethermixture, sodium and potassium.

' Organic solvent complexes of the metallic halides are formed by addingthe halide to the organic solvent followed by stirring. Examples oforganic solvents are benzene, toluene, pentene, decene, diethyl ether,phenyl methyl ether, phenyl ethyl ether, diisopropyl ether, etc.

Metallic halide catalysts (including complexes of .such metallichalides) are well-known to be distinguished as a class by their tendencyto hydrolyze in the presence of water, giving and acid reaction. Theyare therefore frequently designated as acid-acting metallic halides.This term includes the boron halides.

The catalyst employed in the initial reaction may be used as such or inadmixture such as with a suitable solvent to form a suspension, solutionor emulsion. A catalyst when employed in the final reaction may be usedin similar manner.

Likewise, the reactants may be employed as such or in admixture such aswith a suitable solvent, or with additives such as coloring materialsetc. referred to above. The reaction also -may be carried out in theemulsion state by the use of suitable emulsifying agents, such as sodiumoleate.

In order to control more closely the speed and uniformity of thereaction, I prefer to slowly add with thorough agitation, a solution ofthe reactant or reactants to a suspension, solution or emulsion of thecatalyst in an organic solvent.

Since the reaction runs smoother and is much more easily controlledunder these conditions, it has been found possible to more readilyeffect large scale production in this manner.

Examples of suitable solvents or diluents for both catalysts andreactants are benzene, toluene, xylene, solvent naphtha, petroleumnaphtha and carbon tetrachloride.

such as a jacketed vessel provided with an agitator.

The quantity of catalyst may be varied over a rather wide range in boththe initial and the final polymerization reactions, although it is foundpreferable to employ limited quantities such as from 0.1% to 10% byweight of reactants present.

In general, when employing catalysts to polymerize styrene and partiallypolymerized isoprene, temperatures between 60 and C. are suitable. Iprefer, however, to use temperatures between 40 and 60 C.

The upper limit of permissible temperature is largely determined by (1)the concentration of reactants, (2) the concentration of catalyst, and

(3) the reaction time employed. Therefore, if it is found thatpolymerization conditions are sumciently drasticto produce an insolublepolymer or gel when a soluble polymer is desired, one or more of thefour conditions, namely (1) temperature, (2) concentration of reactants,(3) proportion of catalyst, and (4) reaction time should be reduceduntil the desired soluble polymer is obtained.

In general, in both the initial and final polymerizations, it ispreferred to completely remove catalyst from the reaction mass after thedesired polymerization is obtained.

Metallic halides, metallic halide-organic solvent complexes and organicperoxides may be removed by any suitable means, such as treating thereaction mass with an'alkaline solution followed by thorough washingwith water.-

Contact materials may be removed from the reaction mass by settling,filtration, or centrifu ing, or otherwise.

While in the foregoing description reference has not been expressly madeto a change in polymerization agent during any single polymerizationstep, it is to be understood that a change in polymerization agentduring any single polymerization step might be resorted to if desired.

For instance, the initial partial polymerization of isoprene might becarried out in part by the use of a catalyst, the catalyst removed andthe partial polymerization completed by the application of heat. 0n theother hand, heat might be applied initially followed by the use of acatalyst. The use of both heat and catalyst has already been referredto.

Likewise, the polymerization of monomeric styrene with partiallypolymerized isoprene might be efiected in part by the use of heat andcompleted by the use of a catalyst, or the polymerization might bestarted by use of a catalyst, the

catalyst removed and the polymerization comvent vapors, or vapors of thereaction mass, or

in a vacuum. In general, the exclusion of air or oxygen from thematerial during the polymerization process will prevent any possibleformation of undesirable compounds, although this step is by no meansessential.

Furthermore, while it is preferred to carry out the initial catalyticpartial polymerization and the final polymerization with the reactantsat least for the most part in the liquid phase, it is to be understoodthat the reactants might be in the gaseous phase or partly in thegaseous phase and partly in the liquid phase, or one or more of thereactants might be in the form of an emulsion.

While any proportion of partially polymerized isoprene to styrene may beemployed in making my new resin, I prefer in the case of coating com- Onthe other hand, in the case of casting or molding compositions, I preferto employ between 50% and 99% monomeric sigrene to between 50% to 1%partially polymerize isoprene on the undiluted basis. 70% to 95%monomeric styrene to to 5% partially polymerized isoprene is verysuitable.

The resin obtained by polymerizing a mixture containing 90 parts ofmonomeric styrene to 10 parts of partially polymerized isoprene isexcellent.

In the event of the removal of extraneous materials, such as'unpolymerized material from the partially polymerized isoprene andhydrocarbons of similar boiling point from styrene, a highly superiorproduct is obtained even though a polymerization diluent such asbenzene, toluene, etc., is employed.

While when partially polymerized isoprene is present in greaterproportion in the reaction mass, the resulting resin is ideally suitedto the coating of surfaces in general, such as of metal, wood, glass,ceramic substances, etc., and particularly to the coating of metalsurfaces, it may be used for any other purposes, for instance, forlacquers generally, for varnishes either alone or in admixture withother resins, for enamels, for paints, for coating compositionsgenerally, or perhaps if desired for casting and molding particularlywhen the spread in proportion of reactants is not too great.

While when styrene is present in larger proportion in the reaction mass,the resulting resin is ideally suited for casting or molding purposes,in which it may be employed alone or in admixture with other plasticsor resins either with or without the addition of coloring agents,fillers,

etc., it is conceivable that, ifdesired, the resin might be used forcoating purposes particularly if the spread in proportion of reactantsis not too great Furthermore, while with the catalyst employed in theinitial catalytic partial polymerization step and when a catalyst isemployed in the final polymerization step it is preferred to have boththe catalyst and the reactants in diluted form and to add the reactantsolution to the diluted catalyst, it is to be understood that any otherprocedure might be followed-without departing from the broad concept ofthe invention. For instance, all of the diluent may be first mixed witheither the catalyst or the reactant or reactants leaving the other inconcentrated form.

Or the larger part of the diluent may be added to one, thus leaving theother relatively concentrated. On the other hand, both the catalyst andthe reactant or reactants might be employed in concentrated form,particularly if the observations herein with respect to (1) proportionof cat alyst, (2) temperature, and (3) reaction time are followed.

It will be understood that any other suitable alkali, such as sodiumhydroxide, sodium carbonate, sodium bicarbonate, 7 magnesium hydroxide,an amine or other basic substance might be substituted for lime in theremoval of catalyst, preferably followed by a non-acidic drying agentsuch as sodium sulphat or soda lime. Both neutralizing and drying iseffected by lime. Neutralization is preferably followed by filtration,centrifuging or settling to remove extraneous solids.

While I have spoken rather disparagingly of the insoluble type of resin,this is because it is also generally infusible and, therefore, has fewif any important uses at the present time. Should an important usedevelop for a resin which is insoluble andinfusible before use myProcess may likewise be used to obtain this material in good yield byemploying drastic conditions as to (1) concentration of reactants, (2)concentration of catalyst, (3) temperature, and (4) reaction time. It isto be understood that while it is preferred to change all orsubstantially all of the monomeric isoprene to partially polymerizedisoprene during the initial polymerization reaction, suchinitialpolymerization may be conducted in such a manner as to polymerizonly a part of the isoprene present without departing from the spirit ofthe invention.

It will be understood that there may be employed not only pure andsubstantially pure monomeric styrene, commercial but also technicalgrades thereof, and any mixture or fraction in which monomeric styreneis the predominating activ material of said mixture or fraction in thepolymerization reaction with partially polymerized isoprene.

It will be understood that there may be employed not only pure andsubstantially pure monomeric isoprene, commercial but also technicalgrades thereof, and any mixture or fraction in which monomeric isopreneis the predominating active material of said mixture or fraction in thepartial polymerization thereof.

When percentages of styrene and partially.

polymerized isoprene are expressly recited in the claims, these areintended to express the propor-- tions of these specific compounds onthe undiluted basis, that is irrespective of thepresence of othermaterial.

The term acid-acting metallic halide catalyst as used in the claims, andfled, is intended to include within its scope not only acid-actingmetallic halides per se but also complexes thereof such as the organicsolvent complexes as fully described in the foregoing specification. Theterm acid-acting metallic halides is likewise intended to include withinits scope boron halides as well as complexes thereof.

It is to be understood that the above particular description is by wayof illustration and that changes, omissions, additions, substitutions,and/or modifications might be made within the scope of the claimswithout departing from the limited only as required by the prior art.

unless otherwise modi- I claim:

1. A synthetic resin comprising the product resulting irom thepolymerization of styrene with isoprene which has been previouslypartially polymerized cataLvtlcally with the aid of an acid-actingmetallic halide catalyst.

2. A synthetic resin comprising the product resulting from thepolymerization of a light 'oil styrene fraction in which styrene is thepredominating active compound with isoprene which has been previouslypartially polymerized catalytically with the aid of an acid-actingmetallic halide catalyst.

3. A synthetic resin comprising the product re-' sulting from thepolymerization of styrene with a light oil isoprene fraction which hasbeen previously partially polymerized catalytically with the aid of anacid-acting metallic halidecatalyst, said light oil isoprene fractionprior to said partial polymerization containing more isoprene than anyother diolenne,

4. A synthetic resin comprising the product resulting from thepolymerization of a light oil styrene fraction in which styrene is thepredominating active compound with a light oil isoprene fraction whichhas been previously partially polymerized catalytically with the aid ofan acidacting metallic halide catalyst, said light oil isoprene fractionprior to said partial polymerization containing more isoprene than otherdioleflnic material.

5.-A new resinous composition for use in liquid coating compositionscomprising the product of the polymerization of from 50 to 99% isoprenewhich has been previously partially polymerized catalytically with theaid of an acid-acting metallic halide catalyst with from 1 to 50%styrene.

6. A new resinous composition for use in molding compositions comprisingthe product of the polymerization from 50 to 99% styrene with from 50 to1% isoprene which has been previously partially polymerizedcatalytically with the aid of an acid-acting metallic halide catalyst.

7 A new resinous composition ior use in liquid coating compositionscomprising the product of the polymerization of from 60 to 90% isoprenewhich has been previously partially polymerized catalytically with theaid of an acid-acting metallic halide catalyst with from 40 to 10%styrene.

8. A new resinous composition for use in molding compositions comprisingthe product of the polymerization of from 70 to 95% styrene with from 30to isoprene which has been previously partially polymerizedcatalytlcally with the air of an acid-acting metallic halide catalyst.

9. A varnish having incorporated therein the product resulting from thepolymerization of styrene with isoprene which has been previouslypartially polymerized catalytically with the aid of an acid-actingmetallic halide catalyst.

10. A liquid coating composition comprising the product of claim 5dissolved in a volatile solvent.

11. A molding composition comprising the product resulting from thepolymerization of from 50 to 99% highly concentratedstyrene with 1mm 1to 50% isoprene which has been previously partially polymerizedcatalytically with the aid of an acid-acting metallic halide catalyst.

,' 12. A molding composition comprising the product resulting from thepolymerization of from 50 to 99% highly concentrated styrene with from 1to 50% highly concentrated isoprene which has been previously partiallypolymerized catalytically with the aid of an acid-acting metallic halidecatalyst.

13. A process comprising polymerizing styrene with isoprene which hasbeen previously partially polymerized catalytically with the aid of anacid-acting metallic halide catalyst.

14. A process comprising heat polymerizing styrene with isoprene whichhas been previously partially polymerized catalytically with the aid ofan acid-acting metallic halide catalyst.

15. A process comprising polymerizing a light oil styrene fraction inwhich styrene is the predominating active compound and obtained in themanufacture of oil gas with a'light oil isoprene fraction which has beenpreviously partially polymerized catalytically with the aid of anacid-acting metallic halide catalyst, said light oil isoprene fractionhaving been obtained in the manufacture of oil gas and prior to saidpartial polymerization having contained more isoprene than otherdiolefinic material.

16. A synthetic resin comprising the product resulting from the heatpolymerization of monomeric styrene with isoprene which has been pre-,viously partially polymerized catalytically with theaid of anacid-acting metallic halide catalyst.

17. A new resinous composition comprising the thermoplastic productresulting from the heat polymerization of from 60 to isoprene which hasbeen previously partially polymerized catalytically with the aid of anacid-acting metallic halide catalyst with from 40 to 10% monomericstyrene.

18. A new resinous composition comprising the thermoplastic productresulting from the heat polymerization of from '70 to monomeric styrenewith from 30 to 5% isoprene which has been previously partiallypolymerized catalytically with the aid of an acid-acting metallic halidecatalyst. O

19. A process for the copolymerization of styrene and a light oilisoprene fraction at least 50% in isoprene concentration, comprisingsubjecting said light oil isoprene fraction to polymerizing conditionsin the presence of an acidacting metallic halide catalyst whilemaintaining the temperature throughout the reaction mass not in excessof C., the concentration

